Gibbons writes extensively about Byzantium, state and church. I haven't finished my version, but it is going beyond the fall of the western empire. Chapter 71 covers 1430 AD. Of course, there are many abridged versions that may end abruptly, but mine doesn't. What is it, stylish now to trash Gibbons? His history is not perfect but still a benchmark by which others are measured.
Stylish? No, but something Christians have been doing since he came up with the unsupportable notion the Christianity weakened the Empire, causing it to fall. He was “trashed” in his own day for it. The notion is unsupportable precisely because the Empire lasted over a thousand years as a formally Christian Empire (from Theodosius’s formal adoption of Christianity as the Imperial religion in 380 until the Fall of Constantinople to the Turks in 1453).